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    <title>Document</title>
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  <body></body>
  <script>
    function User() {}
    User.prototype.getUserName = function () {};

    function Admin() {}
    Admin.prototype = Object.create(User.prototype);
    console.log(Admin.prototype.__proto__ == User.prototype);
    Admin.prototype.role = function () {};

    function Member() {}
    Member.prototype = Object.create(User.prototype);
    Member.prototype.email = function () {};
    console.log(new Admin());
    console.log(new Member());
  </script>
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